Friday, January 23, 2015

Barrier guards are often used to protect the worker from hazards.When frequent access is required you may find the need to use door safety switches.These are important devices used to detect when an access point is closed or covered.There are many different types and here are some things to consider in selecting them.The right door switch for the application ensures that they remain in good working order and are always part of your safeguarding plan.

One of the key distinctions between switches is whether they are mechanical connection or non-contact.Switches can have a mechanical connection like a key that must be engaged for the switch to be closed.Non-contact are sensors that have two sides that detect each other when closed.Switches need to be not easily defeatable so many changes have occurred on how both these types of switches have been manufactured.The mechanical connection ones have more complex key systems that are not easily duplicated and bypassed. The non-contact switches have different means of detection so they are not so easily tripped by magnets or tape.There are many different types of door safety switches on the market.

Some of the considerations that can help select a switch:

1.Do you need the switch to stay locked until a cycle is complete?Is there instant stop of a hazard when the switch is opened?If someone opens an access point, is there still a hazard that can be accessed that requires time to power down (like a rotating hazard)?This is where a timed switch or one that is tied to a sensor that only unlocks when a condition is met.

2.What is the weight or size of the access point?Is this a gate that needs to slide into place?Is it heavy enough where a switch can be easily broken?Switches are manufactured depending on the action (sliding or hinged) and the relative force placed on them.

3.What is the frequency of access?What is the speed of the closing or opening?These are important points to consider when selecting a switch.

Finally it’s always important that the door switches are tied in correctly to the safety control system, whether that’s a safety relay or safety controller.If you are having trouble with your safety switches, give us a call.